Optimal sequential control strategy of central air conditioningcooling towers with multi-parameter collaboration

Variable frequency control is a commonly used energy-saving control strategy for central air conditioning cooling towers. When the load is light, there are often few fans operating at high frequency, resulting in a large waste of energy consumption. This study proposes an optimal sequential control strategy with multi-parameter collaboration for cooling towers, which balances the fan on/off frequency and energy consumption by the sequential control parameter. Further, the regular characteristics between the sequential control parameter and both the fan on/off frequency and energy consumption under different load conditions are studied to provide a basis for setting the sequential control parameter. A test platform is established based on a real central air conditioning cooling water system to validate the control performance of the optimal sequential control strategy. The results show that, compared with the conventional control strategy, the optimal sequential control strategy achieves 8.63% energy consumption reduction under medium load conditions (37%-69% of the design cooling load) when the same cooling performance is obtained. And it is 52.61% energy consumption reduction under light load conditions (23%-40% of the design cooling load). This study provides an effective control method for the high-performance operation of cooling towers.